1. Technical Field
This invention relates to spray devices in general and in particular to a rotating spray nozzle assembly for high pressure water applications such as automatic car washes and the like.
2. Background Art
Typical applications for spray nozzle assemblies include shower heads, lawn sprinklers, paint applicators, and car washes. The main objective of most spray assemblies is to disburse pressurized water over a large surface area. Paint applicators and lawn sprinklers are additionally concerned with the spray pattern, as it is necessary to disperse the pressurized water in a uniform manner. Shower heads, on the other hand, are more concerned with the washing action of the water upon impact with a surface. The spray nozzles for automatic car washes have unique design concerns in that they must deliver a uniform concentration of water over a large area while still providing an effective washing action to the water.
Common rotating lawn sprinklers use directional nozzles to impart a rotational force on their rotating distribution members. The purpose for the rotation is to increase the effective area over which a uniform concentration of water is applied. This directional nozzle apparatus is extremely effective for use with the relatively low water pressures associated with common water lines. The directional nozzle apparatus is however, not well suited for high pressure applications, simply because the angular velocity, or rpm, of the distribution member is directly related to the water pressure. If a directional type nozzle were used in an automatic car wash, which has a water pressure of approxiamtely 1,220 psi, it would result in an extremely high angular velocity and probable disintegration of the nozzle apparatus due to centrifugal effects. Additionally, the tangential orientation of the directional nozzles results in the water droplets having substantial tangential velocities and consequently deliver an unacceptable washing action.
There have been several pertinent developments in the design of shower heads, which are concerned with providing a pulsating spray pattern for therapeutic use. A desirable byproduct of the massaging spray is an increased scrubbing effect of the water upon impingement with a surface. This increased washing action is attributable to the fact that the water impinges the washing surface from a direction which is perpendicular, or normal to the surface. Typical of the pulsating spray head art are the teachings of Bruno, U.S. Pat. Nos. 3,734,410 and 4,018,385, both of which teach similar pulsating spray heads. The spray heads, as taught by Bruno, both use a wobble plate located just prior to the water exit holes. The wobble plate is hydraulically activated to oscillate back and forth. The back and forth motion of the wobble plate produces a therapeutic, pulsating effect. These type of spray heads are unsuitable for high pressure applications such as in a car wash, because of uncontrollable vibrations resulting from the pulsating apparatus. They also produce a very limited sized spray pattern.
What is needed is a high pressure spray nozzle assembly capable of dispersing water over a large surface area which is free from pulsation and delivers spray with a suitable washing action.
Accordingly, it is an object of this invention to provide a rotating spray nozzle assembly for use in automatic car washes which produces a uniform scrubbing spray pattern from a high pressure water source.
Some additional objects of this invention are to provide a rotating spray nozzle assembly wherein the angular velocity of the distribution member can be selected independent of the high pressure water source, and further, to produce a rotating spray nozzle assembly which does not impart a substantial tangential velocity to the spray droplets.